Color-photographic recording material

ABSTRACT

A color-photographic recording material which, in at least one light-sensitive silver halide emulsion layer, an interlayer and/or a protective layer, contains at least one polyalkylpiperidine compound of the formula I ##STR1## in which R is an OH group and R 1  is a group of the formula II ##STR2## or of the formula ##STR3## and X is a group of the formula ##STR4## or of the formula ##STR5## Color images obtained by imagewise exposure and development of this color-photographic recording material show good stability to the action of visible and ultraviolet light. 
     With respect to the definitions of the substituents and symbols in the formulae, reference is made to the description.

The present application relates to a colour-photographic recordingmaterial which, in at least one light-sensitive silver halide emulsionlayer and/or in at least one of the conventional auxiliary layers,contains a specific polyalkylpiperidine compound as a stabiliser.

As sterically hindered amines, polyalkylpiperidines are generally knownas light stabilisers for organic materials, in particular for polymers.In German Offenlegungsschrift 2,126,954, the use of suchpolyalkylpiperidines as agents to counteract the fading of colourphotographs was proposed in the past. Furthermore, EP-A 11,051 proposedthe use of certain polyalkylpiperidine derivatives, which contain atleast one phenol group, as light stabilisers for colour photographs.These are polyalkylpiperidine esters of hydroxybenzylmalonic acids.

It has now been found that polyalkylpiperidine compounds which contain asterically hindered phenol linked via a carboxyalkylidene group orcarbaminoalkylidene group exert a surprisingly improved stabilisingaction.

The subject of the present invention is therefore a colour-photographicrecording material which, in at least one light-sensitive silver halideemulsion layer, an interlayer and/or a protective layer, contains atleast one polyalkylpiperidine compound as a stabiliser, wherein thepolyalkylpiperidine compound is of the formula I ##STR6## in which R isan OH group in the 2-position, 4-position or 6-position, R₁ is hydrogen,C₁ -C₄ -alkyl, a group of the formula II ##STR7## or a group of theformula III ##STR8## R₂ is C₁ -C₄ -alkyl, a group of the formula III ora group of the formula --CO--Y--X, R₃ and R₄ independently of oneanother are C₁ -C₈ -alkyl and, in addition, R₄ can, together with thegroup --(C_(n) H_(2n))--, form a C₅ -C₁₂ -cycloalkyl radical, n is anumber from 1 to 20, m is 1 or 2, A is a direct C--C bond if m=1 or aradical ##STR9## if m=2, Y is --O-- or N(R₅)--, wherein R₅ is hydrogen,C₁ -C₁₈ -alkyl, C₃ -C₁₂ -alkenyl, C₃ -C₁₂ -cycloalkyl, phenyl, C₇ -C₁₄-aralkyl, C₇ -C₁₄ -alkaryl, C₂ -C₁₁ -alkoxyalkyl or a group of theformula IV ##STR10## M is a direct bond, --O--, --S--, --S--S--, --SO--,--SO₂ -- or a group --CH₂ OCH₂ --, --CH₂ SCH₂ --, --CH(R₈)-- or--N(R₉)--, wherein R₈ is hydrogen, C₁ -C₁₂ -alkyl or C₃ -C₈ -alkylinterrupted by 1-3 sulfur atoms and R₉ is hydrogen, C₁ -C₁₈ -alkyl orunsubstituted or C₁ -C₄ -alkyl-substituted phenyl or benzyl, X is agroup of the formula ##STR11## or of the formula ##STR12## a is one ofthe numbers from 0 to 10, b, c and d independently of one another arethe number 0 or 1, it being necessary for the sum a+b+c≠0 if d=1, R₆ ishydrogen or methyl, R₇ is hydroxyl, C₁ -C₁₂ -alkyl, C₃ -C₆-alkenylmethyl, C₃ -C₄ -alkynylmethyl, C₇ -C₁₄ -aralkyl, glycidyl, C₁-C₄ -alkyl substituted by halogen, cyano, --COOR₁₂ or --CON(R₁₃)(R₁₄), agroup --COR₁₅, --COOR₁₂, --CON(R₁₃)(R₁₄), --CH₂ --CH(R₁₆)--OR₁₇,--SOR₁₈, --SO₂ R₁₈, --OR₁₂ or --OCOR₁₅, R₁₂ being C₁ -C₁₂ -alkyl, allyl,cyclohexyl or benzyl, R₁₃ being C₁ -C₁₂ -alkyl, allyl, cyclohexyl,benzyl, phenyl or C₇ -C₁₀ -alkylphenyl, R₁₄ being hydrogen, C₁ -C₁₂-alkyl, allyl, cyclohexyl or benzyl, or R₁₃ and R₁₄, together with the Natom to which they are attached, forming a 5-membered or 6-memberedheterocyclic ring, R₁₅ being hydrogen, C₁ -C₁₂ -alkyl, C₂ -C₆ -alkenyl,chloromethyl, C₅ -C₈ -alkyl, C₇ -C₁₄ -aralkyl, phenyl, C₇ -C₁₀-alkylphenyl or phenyl, phenylmethyl or phenylethyl which aresubstituted by 1 or 2 C₁ -C₄ -alkyls and 1 hydroxyl, R₁₆ being hydrogen,C₁ -C₄ -alkyl, C₃ -C₄ -alkoxyalkyl, phenyl or phenoxymethyl, R₁₇ beinghydrogen, C₁ -C₁₂ -alkyl, a group --COR₁₅ or --CON(R₁₃)(R₁₄) or a groupof the formula ##STR13## in which R₁ ' is hydrogen or C₁ -C₄ -alkyl, andR₁₈ being C₁ -C₁₂ -alkyl, phenyl or C₇ -C₁₀ -alkylphenyl, or R₇ is agroup of the formula ##STR14## in which Q is --(C_(r) H_(2r))-- whereinr is one of the numbers 2 to 12, or Q is C₄ -C₈ -alkenylene, C₅ -C₁₂-cycloalkylene, phenylene, xylylene, bitolylene or a group --CO--(C_(r)H_(2r))--CO--, Z is --O-- or --N(R₁₉)-- wherein R₁₉ is hydrogen, C₁ -C₁₈-alkyl, C₃ -C₁₂ -alkenyl, C₃ -C₁₂ -cycloalkyl, phenyl, C₇ -C₁₄ -alkaryl,C₇ -C₁₄ -aralkyl, C₂ -C₁₁ -alkoxyalkyl or a group --COR₂₀, --COOR₂₁,--CON(R₂₂)(R₂₃), --CH₂ --CH(R₂₄)--OR₂₅, --SOR₂₆ or --SO₂ R₂₆, R₂₀ havingone of the meanings defined for R₁₅ or being a heterocyclic ring, R₂₁having one of the meanings defined for R₁₂, R₂₂ having one of themeanings defined for R₁₃, R₂₃ having one of the meanings defined forR₁₄, R₂₄ having one of the meanings defined for R₁₆, R₂₅ having one ofthe meanings defined for R₁₇ and R₂₆ having one of the meanings definedfor R₁₈, or R₁₉ is a group of the formula IV, R₁₀ is hydrogen, C₁ -C₁₈-alkyl, C₇ -C₂₃ -phenoxyalkyl, phenyl, C₇ -C₁₄ -aralkyl, C₂ -C₁₁-alkoxyalkyl or a group ##STR15## R₁₁ is hydrogen, --OR₂₇, --OCOR₂₈,--N(R₂₉)--COR₂₈, --OSO₂ R₂₈ and --N(R₂₉)--SO₂ R₂₈, R₂₇ being hydrogen,C₁ -C₁₂ -alkyl, allyl or benzyl, R₂₈ being hydrogen, C₁ -C₁₂ -alkyl, C₂-C₆ -alkenyl, chloromethyl, C₅ -C₈ -cycloalkyl, C₇ -C₉ -phenylalkyl, C₇-C₁₀ -alkylphenyl, phenyl or a group of the formula ##STR16## and R₂₉being hydrogen, C₁ -C₁₂ -alkyl, C₅ -C₈ -cycloalkyl or benzyl, and Wbeing one of the groups ##STR17## in which R₃₀ is methyl or ethyl, withthe proviso that, if W is a cyclic ketal structure, d is 0 and the suma+b+c must also be 0 and, if W is a hydantoin structure, d must be 0 andthe sum a+b+c must be ≠0, the repeatedly mentioned radicals and symbolsalways being as defined in the first instance and, with repeatedoccurrence of the group ##STR18## R always being in the same position.

Any alkyl substituents are straight-chain or branched alkyl groups. C₁-C₄ -alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl,sec.-butyl or tert.-butyl. C₁ -C₈ -alkyl groups also include, forexample, n-pentyl, 2,2-dimethylpropyl, n-hexyl, 2,3-dimethylbutyl,n-octyl and 1,1,3,3-tetramethylbutyl. C₁ -C₁₂ -Alkyl groups alsoinclude, for example, nonyl, decyl, undecyl and dodecyl. C₁ -C₁₈ -alkylgroups also include, for example, tetradecyl, hexadecyl, heptadecyl andoctadecyl.

Any C₅ -C₈ -cycloalkyl substituents are, for example, cyclopentyl,cyclohexyl, cycloheptyl, α-methylcyclohexyl, cyclooctyl ordimethylcyclohexyl. C₃ -C₁₂ -cycloalkyl groups also include, forexample, cyclopropyl, cyclononyl, cyclodecyl and cyclododecyl.Cyclohexyl is preferred.

Examples of C₇ -C₉ -phenylalkyl groups R₂₈ are benzyl, phenylethyl andphenylpropyl. Any C₇ -C₁₄ -aralkyl substituents also include, forexample, phenylbutyl and naphthylmethyl.

Any C₇ -C₁₀ -alkylphenyl substituents are, for example, tolyl, xylyl,isopropylphenyl, tert.-butylphenyl and diethylphenyl.

Examples of C₃ -C₆ -alkenylmethyl groups R₇ are allyl, methallyl,dimethylallyl and 2-hexenyl. C₂ -C₆ -alkenyl groups R₁₅ and R₂₈ can alsobe vinyl.

Examples of C₃ -C₁₂ -alkenyl groups R₅ and R₁₉ are allyl, methallyl,2-butenyl, 2-hexenyl, 2-octenyl, 4-octenyl, 2-decenyl and 2-dodecenyl.Allyl is preferred.

C₃ -C₄ -alkynylmethyl groups R₇ are, for example, propargyl,n-but-1-ynyl or n-but-2-ynyl. Propargyl is preferred.

Any C₇ -C₁₄ -alkaryl substituents are, for example, C₁ -C₄-alkyl-substituted phenyl, such as p-tolyl, 2,4-dimethylphenyl,2,6-dimethylphenyl, 2,4-diethylphenyl, 2,6-diethylphenyl,4-tert.-butylphenyl, 2,4-di-tert.-butylphenyl or2,6-di-tert.-butylphenyl. 2,4-Di-tert.-butylphenyl and2,4-dimethylphenyl are preferred.

A heterocyclic ring R₁₅ is, for example, pyrrole, pyridine, indole,quinoline, pyrrolidine, thiophene, furan, imidazole, pyrazine,pyrimidine, thiazole, oxazole, piperazine, morpholine or piperidine.

C₃ -C₄ -alkoxyalkyl groups R₁₆ are, for example, ethoxymethyl,2-methoxyethyl or 2-ethoxyethyl. C₂ -C₁₁ -alkoxyalkyl groups R₅, R₁₀ andR₁₉ also include methoxymethyl, 2-n-butoxyethyl, 2-n-butoxypropyl,2-n-octoxyethyl, 3-n-octoxypropl and 6-n-butoxyphenyl.

Examples of C₇ -C₂₃ -phenoxyalkyl groups R₁₀ are phenoxymethyl,phenoxyethyl, phenoxypropyl, phenoxybutyl, phenoxyoctyl, phenoxydecyl,phenoxydodecyl and phenoxyhexadecyl.

Any halogen substituents are, for example, bromine, iodine or especiallychlorine.

In the group --C_(n) H_(2n) -- with n a number between 1 and 20, n ispreferably a number between 2 and 8 and especially 3. Examples aremethylene, ethylene, trimethylene, tetramethylene, hexamethylene,octamethylene, nonamethylene, 2,2,4-trimethylhexamethylene,decamethylene and dodecamethylene.

Phenyl, phenylmethyl or phenylethyl groups R₁₅ and R₂₀ which aresubstituted by 1 or 2 C₁ -C₄ -alkyls and 1 hydroxyl are, for example,2,5-dimethyl-4-hydroxyphenyl, 3,5-di-tert.-butyl-4-hydroxyphenyl,3,5-dimethyl-4-hydroxybenzyl, 3,5-di-tert.-butyl-4-hydroxybenzyl or2-(3,5-di-tert.-butyl-4-hydroxyphenyl)-ethyl.

Those colour-photographic recording materials are preferred which, asstabilisers, contain at least one compound of the formula Ia ##STR19##in which the substituents R, R₁, R₂, R₃, R₄, Y and X as well as theindex n are as already defined above.

Those colour-photographic recording materials are preferred which, asthe stabiliser, contain at least one compound of the formula V ##STR20##in which R is an OH group in the 2-position, 4-position or 6-position,R₁ is hydrogen, C₁ -C₄ -alkyl, a group of the formula VI ##STR21## or agroup of the formula VII ##STR22## R₂ is C₁ -C₄ -alkyl or a group of theformula VII, Y is --O-- or --N(R₅)--, R₅ being hydrogen, C₁ -C₁₂ -alkyl,cyclohexyl, C₃ -C₄ -alkoxyalkyl or a group of the formula VIII ##STR23##M is --CH(R₈)-- or --S--, R₈ being hydrogen or C₁ -C₄ -alkyl, R₇ ishydroxyl, methyl, allyl, benzyl, 2-hydroxyethyl, acetyl, acroyl or agroup --CON(R₁₃)(R₁₄), wherein R₁₃ is C₁ -C₈ -alkyl, cyclohexyl orphenyl and R₁₄ is hydrogen, C₁ -C₈ -alkyl or cyclohexyl, or R₇ is agroup of the formula ##STR24## in which R₁₆ is hydrogen or methyl, and Wis one of the groups ##STR25## in which R₃₀ is methyl or ethyl, theradicals mentioned repeatedly under this preferred formula always beingas defined in the first instance under this preferred formula and, withrepeated occurrence of the group ##STR26## R always being in the sameposition.

Those colour-photographic recording materials are particularly preferredwhich, as the stabiliser, contain at least one compound of the formulaIX ##STR27## in which R is an OH group in the 2-position, 4-position or6-position, R₁ is hydrogen, C₁ -C₄ -alkyl or a group of the formula X##STR28## R₂ is C₁ -C₄ -alkyl or a group of the formula X, Y is --O-- or--N(R₅)--, wherein R₅ is hydrogen or C₁ -C₈ -alkyl, and R₇ is hydroxyl,methyl, allyl, benzyl, 2-hydroxyethyl, acetyl, acryloyl or a group ofthe formula ##STR29## in which R₁₆ is hydrogen or methyl.

Furthermore, those colour-photographic recording materials are preferredwhich, as the stabiliser, contain at least one compound of the formula Ior of the formula V or of the formula IX, wherein the radical R is inthe 2-position or in the 4-position or in the 6-position.

The compounds of the formula I are novel and as such are likewise asubject of the present invention.

They can be obtained analogously to known compounds, for example thosedescribed in German Offenlegungsschriften 2,456,864, 2,647,452,2,654,058 and 2,656,769. The last stage of the synthesis is either adirect esterification (acid+alcohol or acid chloride+alcohol), atransesterification or an amidation. The polyalkylpiperidine compoundsused as the starting material for the preparation of the compounds ofthe formula I are known. If some of these should still be novel, theycan be obtained analogously to the known compounds.

The sterically hindered phenol derivatives used as starting materialsare novel. These are phenols of the formula XI ##STR30## in which p isone of the numbers 1, 2 and 3 and q is one of the numbers 0, 1 and 2,with the proviso that p+q≦3, R₃₁ is a group of the formula XII ##STR31##in which R₃, R₄, A, m and n are as defined above and Y' is --OR' or--N(R₅)H, R' being hydrogen, methyl or ethyl and R₅ being as definedabove, and R₃₂ is C₁ -C₄ -alkyl or one of the groups ##STR32## in the2-position, 4-position or 6-position relative to the OH group, wherein Mand R₃₁ are as defined above, R₃₃ is C₁ -C₄ -alkyl, s is one of thenumbers 0, 1 and 2, and t is one of the numbers 0 and 1, with theproviso that s+t≦2, not more than one group of the formula XIII or XIVbeing present in the phenol of the formula XI; and provided furthermorethat, if n is 1 or 2 and R' is hydrogen, then m must be 2.

The phenols of the formula XI can be prepared by reacting a phenol ofthe formula XV ##STR33## in which R₃₂ and q are as defined above, andwith the proviso that a group of the formula XIII or XIV must not bepresent more than once in the formula XV and must be in the 2-position,4-position or 6-position relative to the OH group, with a functionalalkylating agent (XXI) which is capable of introducing a group of theformula XII, in the presence of a suitable catalyst.

The alkylation takes place at temperatures between 20 and 170,preferably between 100° and 150° C. Suitable catalysts are Bronstedacids, active earths or metal salts. The Bronsted acids can be organicor inorganic acids or even partial salts thereof. For example, such anacid can be a mineral acid, such as hydrochloric acid, sulfuric acid,perchloric acid or orthophosphoric acid, or an inorganic acidsubstituted by alkyl, aryl or alkaryl, such as methanesulfonic acid,ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid ormethanephosphonic acid, or an organic acid, such as dichloroacetic acid,trichloroacetic acid or trifluoroacetic acid. Examples of suitableactive earths are Fulmont 237® or Fulcat 22®, whilst aluminiumphenoxide, for example, can be used as a metal salt. The active earthsare preferred.

The reaction can be carried out with or without a solvent. Examples ofsuitable solvents are methanol/sulfuric acid or water/sulfuric acid.These solvents also act as catalysts. The compounds of the formula XIare obtained from compounds of the formula XV by reaction with 0.1 to4.0 moles of the alkylating agent (XXI), depending on the meaning of pand q.

Typical representatives of the formula I are listed in Tables I to VIwhich follow.

                                      TABLE I                                     __________________________________________________________________________     ##STR34##                                                                    Stabi-                                                                        liser                                                                         No. n Y           X                                                           __________________________________________________________________________    1   3 O                                                                                          ##STR35##                                                    2 3 O                                                                                          ##STR36##                                                    3 3 O                                                                                          ##STR37##                                                    4 3 O                                                                                          ##STR38##                                                    5 3 O                                                                                          ##STR39##                                                    6 3 O                                                                                          ##STR40##                                                    7 1 O                                                                                          ##STR41##                                                    8 3 O                                                                                          ##STR42##                                                    9 3 NH                                                                                         ##STR43##                                                    10                                                                              3 NH                                                                                         ##STR44##                                                    11                                                                              3 N(CH.sub.3)                                                                                ##STR45##                                                    12                                                                              1 N(CH.sub.3)                                                                                ##STR46##                                                    13                                                                              3                                                                                ##STR47##                                                                                 ##STR48##                                                  __________________________________________________________________________

                                      TABLE II                                    __________________________________________________________________________     ##STR49##                                                                    Stabiliser                                                                    No.         M       R.sub.2  R.sub.7                                          __________________________________________________________________________    14          CH.sub.2                                                                              CH.sub.3 COCH.sub.3                                       15          CH.sub.2                                                                              C(CH.sub.3).sub.3                                                                      COCH.sub.3                                       16          CH.sub.2                                                                              CH.sub.3 COCHCH.sub.2                                     17          CH.sub.2                                                                              CH.sub.3 CH.sub.3                                           18        CH.sub.2                                                                              CH.sub.3                                                                                ##STR50##                                         19        S       C(CH.sub.3).sub.3                                                                      COCH.sub.3                                       20          S       CH.sub.3 CH.sub.3                                           21        S       CH.sub.3                                                                                ##STR51##                                         22        S       C(CH.sub.3).sub.3                                                                      COCHCH.sub.2                                     __________________________________________________________________________

                                      TABLE III                                   __________________________________________________________________________     ##STR52##                                                                    Stabiliser                                                                    No.       M       R.sub.2  R.sub. 7                                           __________________________________________________________________________    23        --      C(CH.sub.3).sub.3                                                                      CH.sub.3                                           24        --      C(CH.sub.3).sub.3                                                                      COCH.sub.3                                           25      CH.sub.2                                                                              C(CH.sub.3).sub.3                                                                       ##STR53##                                           26      S       C(CH.sub.3).sub.3                                                                      CH.sub.3                                           __________________________________________________________________________

                                      TABLE IV                                    __________________________________________________________________________     ##STR54##                                                                    Stabiliser                                                                    No.       M         R.sub.2    R.sub.7                                        __________________________________________________________________________    27        --        C(CH.sub.3).sub.3                                                                        COCH.sub.3                                     28        CH.sub.2  CH.sub.3   COCHCH.sub.2                                   29        S         C(CH.sub.3).sub.3                                                                        COCH.sub.3                                     __________________________________________________________________________

                                      TABLE V                                     __________________________________________________________________________     ##STR55##                                                                    Stabiliser                                                                    No.  R.sub.1                R.sub.2                R.sub.7                    __________________________________________________________________________    30                                                                                  ##STR56##                                                                                            ##STR57##             COCH.sub.3                   31                                                                                ##STR58##                                                                                            ##STR59##                                                                                            ##STR60##                   32                                                                                ##STR61##             CH.sub.3               COCH.sub.3                   33 H                      C(CH.sub.3).sub.3      COCHCH.sub.2               34   C(CH.sub.3).sub.3      C(CH.sub.3).sub.3      COCH.sub.3                 35   C(CH.sub.3).sub.3      C(CH.sub.3).sub.3      CON(C.sub.2 H.sub.5).su                                                       b.2                        __________________________________________________________________________

                                      TABLE VI                                    __________________________________________________________________________     ##STR62##                                                                    Stabiliser                                                                    No.  R.sub.1                                                                             R.sub.2                                                                             Y    X                                                       __________________________________________________________________________    36   C(CH.sub.3).sub.3                                                                   C(CH.sub.3).sub.3                                                                   O                                                                                   ##STR63##                                                37 C(CH.sub.3).sub.3                                                                   C(CH.sub.3).sub.3                                                                   O                                                                                   ##STR64##                                                38 C(CH.sub.3).sub.3                                                                   C(CH.sub.3).sub.3                                                                   O                                                                                   ##STR65##                                                39 C(CH.sub.3).sub.3                                                                   C(CH.sub.3).sub.3                                                                   O                                                                                   ##STR66##                                                40 H     C(CH.sub.3).sub.3                                                                   NH                                                                                  ##STR67##                                              __________________________________________________________________________

The following are further typical representatives of compounds of theformula I: ##STR68##

The stabilizers of the formula I can be incorporated, by themselves ortogether with other compounds, in a known manner into a photographicmaterial.

As a rule, the stabilisers are incorporated, by themselves or togetherwith other compounds, in particular with colour couplers, in the form ofa dispersion into the photographic material, this dispersion eithercontaining no solvent or containing high-boiling or low-boiling solventsor a mixture of such solvents. In a further suitable incorporationmethod, the stabilisers are incorporated, by themselves or together withother compounds, together with a polymer in the form of a latex into thephotographic material.

The dispersions are then used for preparing the layers ofcolour-photographic recording materials. These layers can be, forexample, interlayers or protective layers, but in particularlight-sensitive (blue-sensitive, green-sensitive and red-sensitive)silver halide emulsion layers in which, on development of the exposedrecording material, the blue-green (cyan), purple (magenta) and yellowdyes are formed from the corresponding colour couplers.

The silver halide layers can contain any desired colour couplers, inparticular cyan, magenta and yellow couplers, which are used for formingthe said dyes and hence the colour images.

Since the substrate has an influence on the action and stability of thecompounds of the formula I, those substrates (solvents, polymers) arepreferred which, together with these stabilisers, result in the bestpossible stability of the materials which are to be stabilised.

As a rule, the stabilisers of the formula I are incorporated into layerswhich additionally contain a silver halide dispersion which has beenprepared and sensitised by conventional methods. However, they can alsobe present in layers adjacent to the layers containing silver halide.

The photographic materials according to the invention have aconventional structure and contain conventional components. Thatstructure and those components are, however, preferred which intensifythe activity of the stabilisers of the formula I or at least do notaffect it adversely.

In the photographic recording material according to the presentinvention, the stabilisers of the formula I can, apart from the colourcouplers, additionally also be combined with ultraviolet absorbers orother light stabilisers in the same layer.

If the diffusion transfer method is used, the stabiliser can also beincorporated into a receiving layer.

The colour-photographic materials according to the invention can beprocessed in the known manner. Moreover, during or after processing,they can be treated in a way which further increases their stability,for example by treating in a stabiliser bath of by applying a protectivecoating.

The stabilisers to be used according to the invention are in certaincases also suitable for protecting colour-photographic layers in whichthe dyes are incorporated directly into the emulsion and the image isproduced by selective bleaching.

The quantity of the stabiliser or stabilisers can vary within widelimits and is approximately in the range from 1 to 2,000 mg, preferably100 to 800 and in particular 200-500 mg, per m² of the layer into whichit or they is or are being incorporated.

If the photographic material contains an agent which absorbs ultravioletradiation, this agent can be present together with the stabiliser in onelayer, or even in an adjacent layer. The quantity of ultravioletabsorber or absorbers can vary within wide limits and is approximatelyin the range from 200 to 2,000 mg, preferably 400 to 1,000 mg, per m² ofthe layer in which it or they is or are incorporated. Examples ofultraviolet absorbers are compounds of the benzophenone, acrylonitrile,thiazolidone, benzotriazole, oxazole, thiazole and imidazole types.

The colour images obtained by exposure and development using therecording material according to the invention show very goodlightfastness to visible and ultraviolet light. The compounds of theformula I are virtually colourless, so that there is no discolourationof the images; furthermore, they are highly compatible with theconventional photographic additives present in the individual layers.Due to their high activity, the quantity in which they are used can bereduced, and they are thus prevented from precipitating or crystallisingout, when they are incorporated as an organic solution into the aqueousbinder emulsions which are used for the preparation of photographiclayers. The individual processing steps necessary for the production ofthe colour images after the exposure of the photographic recordingmaterial are not adversely affected by the stabilisers of the formula I.Moreover, the so-called abrasion fog which frequently occurs withblue-sensitive emulsions can be largely suppressed. This can occur, forexample, when mechanical stresses, for example twisting, bending orrubbing, are exerted on photographic materials (silver halide emulsionlayers located on a base of natural or synthetic materials), duringproduction or during the treatment before development (T. H. James, TheTheory of Photographic Process, 4th edition, Macmillan, New York, N.Y.1977, pages 23 et seq, and pages 166 et seq.).

The examples which follow serve to explain the invention in more detail.Parts therein are parts by weight.

PREPARATION OF THE PHENOLIC STARTING MATERIALS Example 1

94 parts of phenol, 14.2 parts of methyl 5-methylhex-5-enoate and 5.0parts of Fulmont 237® are stirred for 20 hours at 110° C. After partialcooling of the reaction mixture, the catalyst is filtered off. After 82parts of phenol have been separated off, this gives methyl5-(4-hydroxyphenyl)-5-methyl-hexanoate with a boiling point of 167°-72°C./O, 65 mbar.

    ______________________________________                                        Analysis for C.sub.4 H.sub.20 O.sub.3                                                       C     H                                                         ______________________________________                                        Found           71.01%  8.60%                                                 Calculated      71.16%  8.83%                                                 ______________________________________                                    

Repeating Example 1 under the conditions indicated in Table VII whichfollows, the sterically hindered phenols listed in Table VII areobtained.

                                      TABLE VII                                   __________________________________________________________________________    Ex-                                Reaction                                   am-                                temper-                                                                            Reaction                              ple                                                                              Phenol    Alkylating agent                                                                            Catalyst                                                                              ature                                                                              time in                               No.                                                                              (parts)   (parts)       (parts) in °C.                                                                      hours                                                                              End product                      __________________________________________________________________________        ##STR69##                                                                               ##STR70##    Al(OPh).sub.3 from Al(0.3)                                                            175  40                                                                                  ##STR71##                         3                                                                               ##STR72##                                                                               ##STR73##    Fulmont 237 ® (5.0)                                                               125  20                                                                                  ##STR74##                         4                                                                               ##STR75##                                                                               ##STR76##    Fulmont 237 ® (5.0)                                                               125  24                                                                                  ##STR77##                         5                                                                               ##STR78##                                                                               ##STR79##    Fulmont 237 ® (5,0)                                                               150  20                                                                                  ##STR80##                         6                                                                               ##STR81##                                                                               ##STR82##    Fulmont 237 ® (10)                                                                120  24                                                                                  ##STR83##                         7                                                                               ##STR84##                                                                               ##STR85##    Fulmont 237 ® (10)                                                                120  24                                                                                  ##STR86##                         8                                                                               ##STR87##                                                                               ##STR88##    Fulmont 237 ® (5,0)                                                               125  20                                                                                  ##STR89##                       __________________________________________________________________________

Example 9

12.5 parts of methyl 5-(2-hydroxy-5-methylphenyl)-5-methylhexanoate(prepared according to Example 5), 14.2 parts of methyl5-methyl-hex-5-enoate and 1.0 part of p-toluenesulfonic acid are heatedfor 8 days on a steam bath. The reaction mixture is then diluted withether, washed with 2N sodium hydroxide solution and then with water andfinally evaporated. After distillation of the remaining oil in vacuo andafter recrystallisation of the distillate from petroleum ether,bis-2,6-(5-methoxycarbonyl-2-methyl-pent-2-yl)-4-methylphenol of meltingpoint 55°-57° C. is obtained.

    ______________________________________                                        Analysis for C.sub.23 H.sub.36 O.sub.5                                                      C     H                                                         ______________________________________                                        Calculated      70.25%  9.01%                                                 Found           70.38%  9.24%                                                 ______________________________________                                    

PREPARATION OF THE STABILISERS OF THE FORMULA I, TO BE USED ACCORDING TOTHE INVENTION

By transesterifying the end products from Examples 1 to 9 byconventional methods with the polyalkylpiperidine compounds ##STR90##the corresponding stabilisers, to be used according to the invention,are obtained.

APPLICATION EXAMPLES

0.087 g of the yellow coupler of the formula ##STR91## and 0.026 g ofone of the light stabilisers indicated in the tables which follow aredissolved in 2.0 ml of a tricresyl phosphate/ethyl acetate mixture (1.5g in 100 ml). 7.0 ml of a 6% gelatine solution, 0.5 ml of an 8% solutionof the wetting agent of the formula ##STR92## in isopropanol/water (3:4)and 0.5 ml of water are added to the above solution, and the mixture isultrasonically emulsified at a power of 100 watt for 5 minutes.

2.0 ml of a silver bromide emulsion having a silver content of 6.0 g perliter, 0.7 ml of a 1% aqueous solution of the hardener of the formula##STR93## and 3.8 ml of water are added to 2.5 ml of the emulsion thusobtained, and the mixture is adjusted to a pH value of 6.5 and coatedonto a subbed, plastis-coated white paper mounted on a glass plate.

After solidification, the plate with the emulsion is dried in acirculating air oven at room temperature.

After 7 days, samples cut to a size of 35×180 mm are exposed behind astep wedge with 3,00 lux x second and then processed by the KodakEktaprint 2® process.

The yellow wedges thus obtained are irradiated in an AtlasWeather-Ometer under a 2,500 W xenon lamp with a total of 42 kJoules/cm²(a comparative sample does not contain any light stabiliser).

The resulting colour density loss is determined by measuring the colourdensity at λ_(max)., using a TR 924A Densitometer® from Messrs. Macbeth.The results are given in the table which follows:

    ______________________________________                                                        Percent loss of                                                               reflectance at the                                            Light stabiliser No.                                                                          maximum                                                       ______________________________________                                        --              36                                                            14              16                                                            40              21                                                            42              21                                                            47              15                                                            ______________________________________                                    

What is claimed is:
 1. A colour-photographic recording material which,in at least one light-sensitive silver halide emulsion layer, aninterlayer and/or a protective layer, contains a light-stabilizingamount of at least one polyalkylpiperidine compound as a stabiliser,wherein the polyalkylpiperidine compound is of the formula I ##STR94##in which R is an OH group in the 2-position, 4-position or 6-position,R₁ is hydrogen, C₁ -C₄ -alkyl, a group of the formula II ##STR95## or agroup of the formula III ##STR96## R₂ is C₁ -C₄ -alkyl, a group of theformula III or a group of the formula --CO--Y--X, R₃ and R₄independently of one another are C₁ -C₈ -alkyl and, in addition, R₄ can,together with the group --(C_(n) H_(2n))--, form a C₅ -C₁₂ -cycloalkylradical, n is a number from 1 to 20, m is 1 or 2, A is a direct C--Cbond if m=1 or a radical ##STR97## if m=2, Y is --O-- or --N(R₅)--,wherein R₅ is hydrogen, C₁ -C₁₈ -alkyl, C₃ -C₁₂ -alkenyl, C₃ -C₁₂-cycloalkyl, phenyl, C₇ -C₁₄ -aralkyl, C₇ -C₁₄ -alkaryl, C₂ -C₁₁-alkoxyalkyl or a group of the formula IV ##STR98## M is a direct bond,--O--, --S--, --S--S--, --SO--, --SO₂ -- or a group --CH₂ OCH₂ --, --CH₂SCH₂₋₋, --CH(R₈)-- or --N(R₉)--, wherein R₈ is hydrogen, C₁ -C₁₂ -alkylor C₃ -C₈ -alkyl or C₃ -C₈ -alkyl interrupted by 1-3 sulfur atoms, andR₉ is hydrogen, C₁ -C₁₈ -alkyl or unsubstituted or C₁ -C₄-alkyl-substituted phenyl or benzyl, X is a group of the formula##STR99## or of the formula ##STR100## a is one of the numbers from 0 to10, b, c and d independently of one another are the number 0 or 1, itbeing necessary for the sum a+b+c≠0 if d=1, R₆ is hydrogen or methyl, R₇is hydroxyl, C₁ -C₁₂ -alkyl, C₃ -C₆ -alkenylmethyl, C₃ -C₄-alkynylmethyl, C₇ -C₁₄ -aralkyl, glycidyl, C₁ -C₄ -alkyl substituted byhalogen, cyano, --COOR₁₂ or --CON(R₁₃)--(R₁₄), a group --COR₁₅,--COOR₁₂, --CON(R₁₃) (R₁₄), --CH₂ --CH(R₁₆)--OR₁₇, --SOR₁₈, --SO₂ R₁₈,--OR₁₂ or --OCOR₁₅, R₁₂ being C₁ -C₁₂ -alkyl, alkyl, cyclohexyl orbenzyl, R₁₃ being C₁ -C₁₂ -alkyl, alkyl, cyclohexyl, benzyl, phenyl orC₇ -C₁₀ -alkylphenyl, R₁₄ being hydrogen, C₁ -C₁₂ -alkyl, allyl,cyclohexyl or benzyl, or R₁₃ and R₁₄, together with the N atom to whichthey are attached, forming a 5-membered or 6-membered heterocyclic ring,R₁₅ being hydrogen, C₁ -C₁₂ -alkyl, C₂ -C₆ -alkenyl, chloromethyl, C₅-C₈ -alkyl, C₇ -C₁₄ -aralkyl, phenyl, C₇ -C₁₀ -alkylphenyl or phenyl,phenylmethyl or phenylethyl which are substituted by 1 or 2 C₁ -C₄-alkyls and 1 hydroxyl, R₁₆ being hydrogen, C₁ -C₄ -alkyl, C₃ -C₄-alkoxyalkyl, phenyl or phenoxymethyl, R₁₇ being hydrogen, C₁ -C₁₂-alkyl, a group --COR₁₅ or --CON(R₁₃) (R₁₄) or a group of the formula##STR101## in which R₁ is hydrogen or C₁ -C₄ -alkyl, and R₁₈ being C₁-C₁₂ -alkyl, phenyl or C₇ -C₁₀ -alkylphenyl, or R₇ is a group of theformula ##STR102## in which Q is a group --(C_(r) H_(2r))-- wherein r isone of the numbers 2 to 12, or Q is C₄ -C₈ -alkylenylene, C₅ -C₁₂-cycloalkylene, phenylene, xylylene, bitolylene or a group --CO--(C_(r)H_(2r))--CO--, Z is --O-- or --N(R₁₉)-- wherein R₁₉ is hydrogen, C₁ -C₁₈-alkyl, C₃ -C₁₂ -alkenyl, C₃ -C₁₂ -cycloalkyl, phenyl, C₇ -C₁₄ -alkaryl,C₇ -C₁₄ -aralkyl, C₂ -C₁₁ -alkoxyalkyl or a group --COR₂₀, --COOR₂₁,--CON(R₂₂) (R₂₃), --CH₂ --CH(R₂₄)--OR₂₅, --SOR₂₆ or --SO₂ R₂₆, R₂₀having one of the meanings defined for R₁₅ or being a heterocyclic ring,R₂₁ having one of the meanings defined for R₁₂, R₂₂ having one of themeanings defined for R₁₃, R₂₃ having one of the meanings defined forR₁₄, R₂₄ having one of the meanings defined for R₁₆, R₂₅ having one ofthe meanings defined for R₁₇ and R₂₆ having one of the meanings definedfor R₁₈, or R₁₉ is a group of the formula IV, R₁₀ is hydrogen, C₁ -C₁₈-alkyl, C₇ -C₂₃ -phenoxyalkyl, phenyl, C₇ -C₁₄ -aralkyl, C₂ -C₁₁-alkoxyalkyl or a group ##STR103## R₁₁ is hydrogen, --OR₂₇, --OCOR₂₈,--N(R₂₉)--COR₂₈, --OSO₂ R₂₈ and --N(R₂₉)--SO₂ R₂₈, R₂₇ being hydrogen,C₁ -C₁₂ -alkyl, allyl or benzyl, R₂₈ being hydrogen, C₁ -C₁₂ -alkyl, C₂-C₆ -alkenyl, chloromethyl, C₅ -C₈ -cycloalkyl, C₇ -C₉ -phenylalkyl, C₇-C₁₀ -alkylphenyl, phenyl or a group of the formula ##STR104## and R₂₉being hydrogen, C₁ -C₁₂ -alkyl, C₅ -C₈ -cycloalkyl or benzyl, and Wbeing one of the groups ##STR105## in which R₃₀ is methyl or ethyl, withthe proviso that, if W is a cyclic ketal structure, d is 0 and the suma+b+c must also be 0 and, if W is a hydantoin structure, d must be 0 andthe sum a+b+c must be ≠0, the repeatedly mentioned radicals and symbolsalways being as defined in the first instance and, with repeatedoccurrence of the group ##STR106## R always being in the same position.2. A colour-photographic recording material according to claim 1,wherein each radical R in the compounds of the formula I is in the6-position.
 3. A colour-photographic recording material according toclaim 1, wherein each radical R in the compounds of the formula I is inthe 4-position.
 4. A colour-photographic recording material according toclaim 1, wherein each radical R in the compounds of the formula I is inthe 2-position.
 5. A colour-photographic recording material according toclaim 1, which contains, as the stabiliser, at least onepolyalkylpiperidine compound of the formula Ia ##STR107##
 6. Acolour-photographic recording material according to claim 1, whichcontains, as the stabiliser, at least one polyalkylpiperidine compoundof the formula V ##STR108## in which R is an OH group in the 2-position,4-position or 6-position, R₁ is hydrogen, C₁ -C₁₄ -alkyl, a group of theformula VI ##STR109## or a group of the formula VII ##STR110## R₂ is C₁-C₄ -alkyl or a group of the formula VII, Y is --O-- or --N(R₅)--, R₅being hydrogen, C₁ -C₁₂ -alkyl, cyclohexyl, C₃ -C₄ -alkoxyalkyl or agroup of the formula VIII ##STR111## M is --CH(R₈)-- or --S--, R₈ beinghydrogen or C₁ -C₄ -alkyl, R₇ is hydroxyl, methyl, allyl, benzyl,2-hydroxyethyl, acetyl, acroyl or a group --CON(R₁₃) (R₁₄), wherein R₁₃is C₁ -C₈ -alkyl, cyclohexyl or phenyl and R₁₄ is hydrogen, C₁ -C₈-alkyl or cyclohexyl, or R₇ is a group of the formula ##STR112## inwhich R₁₆ is hydrogen or methyl, and W is one of the groups ##STR113##in which R₃₀ is methyl of ethyl, the radicals repeatedly mentioned inthis claim always being as defined in this claim in the first instanceand, with repeated occurrence of the group ##STR114## R always being inthe same position.
 7. A colour-photographic recording material accordingto claim 6, wherein each radical R in the compounds of the formula V isin the 6-position.
 8. A colour-photographic recording material accordingto claim 6, wherein each radical R in the compounds of the formula V isin the 4-position.
 9. A colour-photographic recording material accordingto claim 6, wherein each radical R in the compounds of the formula V isin the 2-position.
 10. A colour-photographic recording materialaccording to claim 1, which contains, as the stabiliser, at least onepolyalkylpiperidine compound of the formula IX ##STR115## in which R isan OH group in the 2-position, 4-position or 6-position, R₁ is hydrogen,C₁ -C₄ -alkyl or a group of the formula X ##STR116## R₂ is C₁ -C₄ -alkylor a group of the formula X, Y is --O-- or --N(R₅)--, wherein R₅ ishydrogen or C₁ -C₈ -alkyl, and R₇ hydroxyl, methyl, allyl, benzyl,2-hydroxyethyl, acetyl, acryloyl or a group of the formula ##STR117## inwhich R₁₆ is hydrogen or methyl.
 11. A colour-photographic recordingmaterial according to claim 10, wherein each radical R in the compoundsof the formula IX is in the 6-position.
 12. A colour-photographicrecording material according to claim 10, wherein each radical R in thecompounds of the formula IX is in the 4-position.
 13. Acolour-photographic recording material according to claim 10, whereineach radical R in the compounds of the formula IX is in the 2-position.14. A colour-photographic recording material according to claim 1, whichcontains, as the stabiliser, a polyalkylpiperidine compound of theformula XVI ##STR118##
 15. A colour-photographic recording materialaccording to claim 1, which contains, as the stabiliser, apolyalkylpiperidine compound of the formula XVII ##STR119##
 16. Acolour-photographic recording material according to claim 1, whichcontains, as the stabiliser, a polyalkylpiperidine compound of theformula XVIII ##STR120##
 17. A colour-photographic recording materialaccording to claim 1, which contains, as the stabiliser, apolyalkylpiperidine compound of the formula XIX ##STR121##
 18. Acolour-photographic recording material according to claim 1, whichcontains, as the stabiliser, a polyalkylpiperidine compound of theformula XX ##STR122##
 19. A colour-photographic recording materialaccording to claim 1, which contains a stabiliser of the formula I incombination with cyan, magenta and yellow couplers.
 20. Acolour-phtographic recording material according to claim 1, whichcontains a stabiliser of the formula I in combination with anultraviolet absorber.
 21. A colour-photographic recording materialaccording to claim 20, wherein the ultraviolet absorber is a compound ofthe benzophenone, acrylonitrile, thiazolidone, benzotriazole, oxazole,thiazole or imidazol types.
 22. A colour-photographic recording materialaccording to claim 1, which contains the stabiliser of the formula I incombination with cyan, magenta and yellow couplers and with ultravioletabsorbers in the same layer.
 23. A colour-photographic recordingmaterial according to claim 1, which contains 1 to 2,000 mg of thestabiliser of the formula I per m² of the layer into which it isincorporated.
 24. A process for the production of photographic colourimages by imagewise exposure and colour development of acolour-photographic recording material according to claim 1.